Method of building boats with twin hulls

ABSTRACT

A method of building boats of the catamaran type. Thus, during the building of a boat which will have twin hulls, a pair of single hull boats are simultaneously launched, with these boats fixed to each other in side-by-side relation. The thus-launched boats are then separated and laterally displaced one with respect to the other up to a predetermined distance therebetween, while one of the boats is guided for movement with respect to the other along a path extending in a precisely perpendicular direction horizontally across the decks of both boats. This guiding of the boats during their lateral displacement with respect to each other is brought about by fixing at least one beam on one of the boats extending perpendicularly across and beyond the other boat, and then mounting on this other boat a guide frame structure which extends around the beam to cooperate therewith during the lateral displacement of the boats from each other. After the boats have been positioned in this way, they are interconnected with a connecting structure which extends between the hulls.

United States atet [1 1 Sakura June 12, 1973 METHOD OF BUILDING BOATSWITH TWIN HULLS [75] Inventor:

[22] Filed: May 25, 1970 [21] Appl. No.: 40,152

Shoichi Sakura, Shimizu, Japan [52] US. Cl. 114/77 R, 114/61 [51] Int.Cl B63b 3/02 [58] Field of Search 114/77 R, 77 A, 61,

114/65, 56, 83, 26-30, 123, 235 R, 43.5, 72, 28; 9/2 R, 2 C, 2 F, 2 S,6, 6.5

Primary ExaminerMilton Buchler Assistant Examiner-Stuart M. GoldsteinAttorneySteinberg & Blake [57] ABSTRACT A method of building boats ofthe catamaran type. Thus, during the building of a boar which will havetwin hulls, a pair of single hull boats are simultaneously launched,with these boats fixed to each other in sideby-side relation. Thethus-launched boats are then separated and laterally displaced one withrespect to the other up to a predetermined distance therebetween, whileone of the boats is guided for movement with respect to the other alonga path extending in a precisely perpendicular direction horizontallyacross the decks of both boats. This guiding of the boats during theirlateral displacement with respect to each other is brought about byfixing at least one beam on one of the boats extending perpendicularlyacross and beyond the other boat, and then mounting on this other boat aguide frame structure which extends around the beam to cooperatetherewith during the lateral displacement of the boats from each other.After the boats have been positioned in this way, they areinterconnected with a connecting structure which extends between thehulls.

9 Claims, 6 Drawing Figures PAIENIED JUN I 2 I973 SKUINZ FIG.

NNNNNNNWNAVW INVENTOR .S'HO/CH/ SA KURA ,F'M RNEYS FIG.5

INVENTOR 57/0/61 .54 KUP/I BY I A RNEYS METHOD OF BUILDING BOATS WITHTWIN HULLS BACKGROUND OF THE INVENTION The present invention relates toboat building methods.

In particular, the present invention relates to the building of boats ofthe catamaran type. During conventional building of boats which havetwin hulls, the hull building procedure takes place on the slipways.However, experience has demonstrated that it is impossible to build atwin hulled boat of large size on ordinary slipways.

Attempts have been made to build a catamaran type of boat simply byfixing to each other single hull boats with a desired spacingtherebetween, after such boats have been built on slipways and launchedinto the sea. However, considerable difficulties are encountered byfollowing this type of procedure. It is unavoidable that there will beconsiderable differences between the two boats in draught, trim andheel, respectively, even though the ballast and weight are adjusted. Ithas thus proved to be extremely difficult with these operatingprocedures to connect in a precise manner a pair of boats which areseparately towed at predetermined relative positions while being underthe influence of waves and winds.

SUMMARY OF THE INVENTION It is accordingly a primary object of thepresent invention to provide a method which will avoid the abovedrawbacks.

In particular, it is an object of the invention to provide a methodwhich makes it possible to build boats of the catamaran type in a highlyprecise manner even though the boats are of a relatively large size.

In particular, it is an object of the invention to provide a methodwhich makes it possible to achieve a precise positioning of single hullboats with respect to each other in preparation for interconnecting themin order to form the twin-hull boat.

According to the method of the invention a pair of single hull boats aresimultaneously built on slipways and are fixed to each other in aside-by-side relation. In this condition they are launched and thensubsequent to launching they are separated and then displaced laterallyone with respect to the other to achieve the required distance betweenthe single hull boats. During this lateral displacing of the boats withrespect to each other they are precisely guided by a beam fixed to andextending laterally beyond one of the boats across and beyond the otherof the boats with this other boat having a guide frame structuresurrounding and coacting with the beam so as to achieve a precise guidedmovement of the boats laterally from each other during displacement toachieve the required distance therebetween. The beams and guide framestructures used to guide the boats during their lateral displacementapart from each other are installed prior to separating of the boatsfrom each other in the condition they had during building on. theslipways. The initial separation of the two ships from each other takesplace after they have been launched and while they are on the sea. Whenthe desired distance between the boats is achieved, they are joined toeach other while maintained precisely at the desired positions withrespect to each other by providing a connecting structure situatedbetween and in terconnecting the boats.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way ofexample in the accompanying drawings which form part of this applicationand in which:

FIG. 1 is a schematic end view of a pair of boats which are still onslipways, FIG. 1 illustrating the beam and guide frame structure used inthe method of the invention;

FIG. 2 is a schematic representation of the manner in which the boatsare displaced laterally from each other after they are launched and cutapart from each other;

FIG. 3 is a schematic plan view of the procedure illustrated in FIG. 2;

FIG. 4 is a schematic transverse elevation showing the details of theguide frame structure and the cross section of a beam extendingtherethrough;

FIG. 5 is a schematic representation, in a transverse view similar tothat of FIG. 4, of the manner in which final minor precision adjustmentsare carried out; and

FIG. 6 is a schematic end elevation of the completed vessel.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, it will beseen that a pair of single hull boats l and 1' are built on slipways 5and are fixed to each other in side-by-side relation by the single hulljoint portion 4. When the single hull boats l and l of FIG. 1 are in acondition illustrated in FIG. 1, they are launched from the slipways 5.

However, a guide structure is first provided, if convenient. This guidestructure includes an elongated beam 2 of box-shaped configuration incross section fixed to the deck 11' of the boat 1 and extendingtherefrom perpendicularly across and beyond the deck 11 of the boat 1. Apair of guide frame structures 3 are mounted on the deck 11 surroundingthe beam 2 so as to coact therewith for the precise guiding of the boatsduring their displacement apart from each other, as described below.While these components 2 and 3 are shown mounted on the boats 1 and 1'prior to the launching thereof in FIG. 1, it is to be noted that undercertain circumstances it is not convenient to mount these componentsbefore launching. Thus, it may happen that the installation of beams 2and guide frame structures 3 will impede the construction work and themovement of equipment such as cranes and the like around the slipways.Under these latter circumstances it is possible to mount the guidestructure 2,3 on the boats subsequent to the launching thereof.

Considered in greater detail, as can be seen from FIG. 3 in particular,a pair of the beams 2 are fixed directly to the deck 11' and extendtherefrom perpendicularly across and beyond the boat 1 at the region ofthe bow and stern of the boats. Each beam 2 is surrounded by a pair ofthe guide frame structures 3 which are fixed to the boat 1. Each pair ofguide frame structures 3 is transversely arranged in spaced relationwith respect to each other along a beam 2 and across the deck 11 of theboat 1. After the guide frame structures 3 are mounted in position thebeams 2 can be passed therethrough and fixed to the boat 1,. At theirfree ends the beams 2 carry stop plates 8 which extend beyond the beam 2and are in the nature of end stop flanges for the beams 2.

As is schematically illustrated in FIG. 5, the beam 2 is of arectangular hollow cross section and is reinforced in its interior bysuitable reinforcing means. In addition it is preferred to provide arolling contact for the beam 2 as it moves through the frame structure3. For this purpose the frame structure 3 is provided with rollers 7(FIG. 4) situated along the corners of the cross section of the beam 2for having rolling contact with the exterior surface thereof to providefor the rolling contact during relative movement of the beam 2longitudinally with respect to the frame structure 3.

Thus, either the beam structure 2 and frame structure 3 is mounted priorto or subsequent to launching. In any event, after this guide structureis mounted on the boats as described above, the interconnecting joint 4between the launched single hull boats is cut so that the boats areseparated from each other. Through a suitable chain block or winchinstallation 6, schematically illustrated in FIGS. 1 and 2, the boatswhich had been severed from each other along the joint 4 are displacedapart from each other with the boat 1 advancing laterally toward theleft, as indicated by the arrow in FIG. 2, so that it becomes displacedapart from the boat 1' until the left frame structure 3 of FIG. 2engages the stop 8. This operation is also illustrated in FIG. 3 wherethe solid-line boat 1 is displaced to the dotted line position. Therolling contact achieved for the beams 2 during movement of the framestructures 3 therealong greatly facilitates the separating operation.The stops 8 provide a precisely determined distance between the boats.Furthermore, the beams 2 extend precisely perpendicularly along pathswhich extend horizontally across the boats, so that an extremely precisedisplacement of the boats with respect to each other is achieved.

When the boats are thus separated from each other so as to be situatedat the precisely determined distance from each other, as determined bythe stops 8, or by suitable marks on the beams 2, the frames 3, and thedeck 11, it is possible to carry out minor adjustments bringing about anextremely precise interrelationship of the positions of the boats l and1 with respect to each other. For this purpose the rollers 7 can beremoved, if necessary and an adjusting mechanism as illustrated in FIG.is operated. This mechanism includes locating blocks or jigsrespectively fixed on the one hand to the outer side surfaces of beam 2and on the other hand to the inner side surfaces of the frame structure3. Between these positioning jigs or blocks 10 are arranged jacks 9which can be hydraulic or mechanical jacks capable of expanding orcontracting so as to control the distance between those jig elements 10fixed to the frame structure 3 and those which are fixed to the beam 2.Through this operation of the jacks 9 it is possible to adjust therelative height, heel and trimming to determine in an extremely precisemanner the correlative positions of the single hull boats with respectto each other.

After the boats are thus positioned very precisely with respect to eachother according to the above method of the invention, the beams 2 andframe structures 3 are maintained completely fixed without any furtherpossible movement therebetween, and then a connecting structure (FIG. 6)is positioned between and fixed with the boats thus interconnecting theboats so as to permanently connect them to each other while transferringto this connecting structure the strength for opposing external forces,so that this strength for opposing external forces need no longer becarried out by the components 2 and 3. It is now possible with thethus-interconnected hulls, to remove the box beams 2 and framestructures, since they have been replaced by the connecting structureinterconnecting the boats and newly loaded and fixed, and thus thebuilding of the twin-hull boat is completed.

As is apparent from the above considerations, according to the method ofthe invention the pair of single hull boats are simultaneously launchedwhile temporarily connected to each other at a small distance from eachother. They are then separated and use is made of the beams 2 of thebox-shaped cross section and the guide frame structures 3 until therequired distance between the boats is achieved after cutting of thejoint 4. At this point, practically all of the required adjustments havebeen completed. The adjustments carried out by way of the jacks 9' areextremely minor adjustments. In other words, by using the beams of aboxshaped cross section it is possible for the two single hull boats tobe correlatively positioned on the sea in a manner which is far moreconvenient and far more precise than has hitherto been possible withconventional methods. I

It is to be noted that it is unnecessary to control the metacentricheight (G.M.) of the single hull boat itself, because a pair of thesingle hull boats are connected together under conjoint conditions, sothat they float with a high degree of stability. Although themetacentric height (G.M.) will naturally be positive, the metacentricheight (G.M.) of the twin-hull boats will always be in the positiveregion at any stage of cutting and widening, or in other wordsdisplacing of the boats apart from each other, due to the use of thebeam of box-shaped cross section with its consequent high strength andweight, according to the method of the invention. As a result thebuoyancy tanks and ballast are rendered unnecessary.

It is thus apparent from the above that with the invention the beam ofbox-shaped cross section functions as a displacement guide or jig usedduring increase of the distance between the two boats during shifting ofone with respect to the other to the required distance while providingthrough the roller 7 the rolling contact be tween the guide frames andbeams. In addition, these beams and guide frames are used as positioningand adjusting jigs so as to set and determine the correlative positionsof the boats by shifting, through the use of pushing and pulling forces,the guide frames both horizontally and vertically while the beams extendtherethrough and have the rolling contact therewith. In addition to theabove advantages, the beam of box-shaped cross section functions toprovide a high degree of stability for the single hull boats, preventingany significant heeling from taking place during the operations when theboats are displaced apart from each other, and also they avoid anyunfavorable influence from external forces such as waves and winds whichtend to bring about upsetting through heeling moments caused by thejoint block structure which is loaded on the boat. Furthermore, thebeams of box-shaped cross section provide the important advantage asacting as reinforcement against external forces, thus preserving andmaintaining the hull shapes in their proper configurations andfacilitating the building of the twin-hull boat.

Thus, with the present invention the pair of single hull boats arelaunched while temporarily connected together under conjoint conditionsin relatively close side-by-side relation. Then they are cut apart fromeach other and displaced to the desired distance with respect to eachother utilizing the beam of a box-shaped cross section with its highstrength, so that the pair of single hull boats can be buoyed up with ahigh degree of stability without requiring the use of a buoyancy tankand ballast.

During the continuous shipbuilding operations of catamaran-type boatshaving twin hulls, the beams of box-shaped cross section and the guideframes and other components used during building operations can berepeatedly used over and over since the beams and guide frames, and thecomponents associated therewith will simply be moved from the completedstructure so that it is available for further use on additional boatswhich are to built.

It is thus clear from the above that the method of the invention can beused in the building of marine structures where it is required toconnect even more than two bodies during the building of special shipssimilar to twin-hull boats where the construction takes place largelywhile afloat on the sea.

What is claimed is:

I. In a method of building a boat having twin hulls, the steps ofbuilding a pair of single hull boats on slipways and fixing the boats toeach other in side-by-side relation, simultaneously launching the pairof single hull boats which are fixed to each other in side-by-siderelation, then separating the thus-launched boats from each other,laterally displacing one of the boats while guiding said one boat formovement with respect to the other along a path extending in a preciselyperpendicular direction horizontally across the decks of both boats, andthen fixedly interconnecting the boats with a connecting structureextending between the hulls, including the steps of fixing to one of theboats at least one elongated beam extending perpendicularly from saidone boat across and beyond the other, mounting on the other boat a guideframe structure extending around said beam and cooperating therewithduring lateral displacement of the boats one with respect to the otherfor performing the step of guiding the boats precisely along saidhorizontal path while providing the predetermined distance between theboats.

2. In a method as recited in claim 1, the step of bringing the guideframe structure into engagement with a stop carried by said beam fordetermining the distance between the boats.

3. In a method as recited in claim 1, the step of carrying out minoradjustments between the beam and guide frame structure when the boatsare at said predetermined distance from each other for preciselydetermining the relative positions of the single hull boats prior tointerconnecting of the boats by the joint block structure.

4. In a method as recited in claim 1, the step of providing a rollingcontact between the guide frame structure and the beam during lateraldisplacement of the boats one with respect to the other.

5. In a method as recited in claim 1, the step of providing for saidguide frame structure a pair of guide frames laterally spaced from eachother transversely with respect to the other boat along said beam.

6. In a method as recited in claim 1, the step of connecting a pair ofsaid beams to one said boat adjacent the bow and stern thereof, andextending parallel to each other transversely and perpendicularly acrossthe other boat, and also connecting a pair of said guide frame structureto said other boat surrounding said beams, respectively.

7. The combination of claim 1 and wherein said beam and guide framestructure are mounted on the boats prior to launching thereof.

8. In a method as recited in claim 1 and wherein said beam and guideframe structure are mounted on said boats subsequent to launchingthereof.

9. In a method as recited in claim 1 and wherein after the hulls arefixed to each other by the connecting structure said beam and guideframe structure are removed for further use in the manufacture ofadditional twin-hull boats.

1. In a method of building a boat having twin hulls, the steps ofbuilding a pair of single hull boats on slipways and fixing the boats toeach other in side-by-side relation, simultaneously launching the pairof single hull boats which are fixed to each other in side-by-siderelation, then separating the thus-launched boats from each other,laterally displacing one of the boats while guiding said one boat formovement with respect to the other along a path extending in a preciselyperpendicular direction horizontally across the decks of both boats, andthen fixedly interconnecting the boats with a connecting structureextending between the hulls, including the steps of fixing to one of theboats at least one elongated beam extending perpendicularly from saidone boat across and beyond the other, mounting on the other boat a guideframe structure extending around said beam and cooperating therewithduring lateral displacement of the boats one with respect to the otherfor performing the step of guiding the boats precisely along saidhorizontal path while providing the predetermined distance between theboats.
 2. In a method as recited in claim 1, the step of bringing theguide frame structure into engagement with a stop carried by said beamfor determining the distance between the boats.
 3. In a method asrecited in claim 1, the step of carrying out minor adjustments betweenthe beam and guide frame structure when the boats are at saidpredetermined distance from each other for precisely determining therelative positions of the single hull boats prior to interconnecting ofthe boats by the joint block structure.
 4. In a method as recited inclaim 1, the step of providing a rolling contact between the guide framestructure and the beam during lateral displacement of the boats one withrespect to the other.
 5. In a method as recited in claim 1, the step ofproviding for said guide frame structure a pair of guide frameslaterally spaced from each other transversely with respect to the otherboat along said beam.
 6. In a method as recited in claim 1, the step ofconnecting a pair of said beams to one said boat adjacent the bow andstern thereof, and extending parallel to each other transversely andperpendicularly across the other boat, and also connecting a pair ofsaid guide frame structure to said other boat surrounding said beams,respectively.
 7. The combination of claim 1 and wherein said beam andguide frame structure are mounted on the boats prior to launchingthereof.
 8. In a method as recited in claim 1 and wherein said beam andguide frame structure are mounted on said boats subsequent to launchingthereof.
 9. In a method as recited in claim 1 and wherein after thehulls are fixed to each other by the connecting structure said beam andguide frame structure are removed for further use in the manufacture ofadditional twin-hull boats.